Self-sharpening cutting instrument



i q mu m E EGNAMEFF SELF SHARPENING CUTTING INSTRUMENT Filed Dec. 30, 1925 Ema-mg gag i 1 550- w pg, o thgr i ia tened,as for instance teeth, beginning with the teeth points, the 9 Patented July .1, 1930 a l UNITED STATES/PATENT, orrlcs ALEXANDER IGNATIEFF, F llllIOSClOW RUSSIA snnr-snanrnnme CUTTING ins'rnumnu'r Application filed December 30, 1925, Serial No. 78,471, and in Germany somber 24, 1925.

This invention relates to improvements in by means of a clamp and screw. The supcutting or piercing instruments described porting part 2 is obliquely arranged with re in my prior Patent No. 1,607,083, in which spect to the main part 3' of the tool and is of it is shown, how the said instruments can be softer material than the cutting layer 1. It

composed of several layers of different hardmay sulfice to use only one cutting. layer, ness so as to remain sharp even when worn which together with the supporting part 2 out'in use. r provides a'sufiicient graduation of hardness The inventionconsists therein, that for for conserving the sharpness, but several laytools of the type especially usedv for metal ers of gr'aduated hardness may be provided. 10 cutting, which tools are formed with a front The frontlface 4 of the supporting part 2, face and a rear face confining the cutting guiding-thjudetached chip of the work piece, edge", the rear face is covered by one or may be man-factured so asto have the shown several layers of greater hardness than the hollow shape accordingfto the-natural shape adjoining part-of the tool body. Such tools of the chip, .or it may be caused to assume 15 thus constructed have the advantage of alsuch a shape in the course of being Worn out. ways remaining sharp, whereas in the known According to Fig. 2 a planing or shaping tools with a hard layer applied to the front tool. without an oblique supporting part is face the Wear is only retarded and the cutting provided immediately on its rear face with a edge eventually becomes blunt. strong cutting plate of multiple layers. This 23 The invention also relates to tools manuplate projects freely from the tool body factured according to my improved process, against the cutting edge, and it may also proas hereinafter described. ject laterally so as to be able to cut and throw The. invention is shown in the drawing aside very great and long chips. on several modifications of the tools in ques- According to Fig. 3 a straight line tool on 25 tion. its one longitudinal face, which serves as rear Fig. 1 shows a turning tool.. face, is covered by the cutting layer 1, or Fig. 2 is a planing or shaping tool. manufactured wholly of a plate of piled lay- Fig. 31sastraight turning or planing tool. ers, the hardest of which is the rear layer Fig. 4 is a saw. 1. The front face is rounded in accordance 39 Figs. 5-7 show details of another type of with the shape of the chip. This tool may also be used as a rigidly fastened turning a saw.

Fig; 8 is a backed off circular cutter. or planing tool or also as a tool held by the Fig. 9 is a similar tool. Y hand. Fig. 10 is a crown bore. According to Fig. 4 a saw or a tool, with 35 Figs. 11 and 12 are a drill. finer and broader teeth, such as a file, is 35 Figs. 13 and 14 are a-screwboltcutter. formed by joining together oblique layers Fig. 15 is a detail elevation on an'enlarged in such manner that the hardest layers 1 form 7 scale of the form of the invention shown in 'the rear of the teeth, and the front faces of Fig. 1. v the teeth are constructed in the natural shape In all the figures-two tightly neighbour'ed arising from wear. parallel lines show the hardest layer, to which According to Figs; 5 to 7 a saw is provided a great number of gradually softer layers withtwo parallel rows of teeth of symmetrimay be adjoined. Everylayer may be of a cal shape, seen in the longitudinal direction thickness of one hundredth of. a millimeter of the saw sheet. In this saw a soft central up to far greater thicknesaespeciallyasmuch layer is covered against both lateral faces reater as the material'is soften, with layers of gradually augmented hard- 5 According to Fig.1 a turning tool body is ness, and the whole is formed to a zigzag or covered on its-rear face bya hard cutting corrugated form and planed on the lateral layer 1, which may-be welded to a supporting faces. In this Way on the outer faces of the menses extend in the form of slaves hereas the aljoining parts of the adually softer according to the -i use. Similar saws may red of straight. layers with ally adjon'nsd and enforced cutting layers in ti form of stares or stripes.

According to Fig. 8 a backed off circular "after covered on its spiral faces by the cutting layers, which in accordance with the spiral form have the shape of spiral cylinders or, in circular cutters of special profiles or --hapes. the corresponding pr file shape with spiral leading lines.

iiccording to Fig. 9 a similar tool has the layers forming the teeth of such length, that they cover each other in two or multiple layers. Every such pile of layers may be of a length ,suificing for running several times r iii llikl ii around the whole tool, so that this latter may have a large original diameter and may be worn out up to a very small diameter without losing its sharpened and original profile.

According to Fig. 10 a crown bore is formed of cutting layers of screw surface shape, four such piles of layers being wound together so as to form on one end four cut-- ting teeth. A central channel is provided, and this channel as well as the outer shape of the tool is conical so as to leave a free space suilicient for avoiding undue friction between the tool and the work piece.

According to Figs. 11 and 12 a drill is composed of a handle or shaft and a drill head 6. The drill head (3 corresponds to the tool shown in Fig. with the exception that only two screw windings are provided, between which free spaces are left for throwing out the chips, instead of a central channel. Moreover aconical point of the drill is produced by forming tln. screw faces with a generating line disposed obliquely with respect to the drill axis so as to generate a cutting edge which lies on a cone, i. e. obliquely in a radial plane. This drill head 6 may be welded to the shaft 5 or, as shown, connect-ed to it by a centering pin 7. The drill head is rotated with the shaft by the rear ends 8 of its screw shaped layers being caught by corresponding axially projecting ends 9 of the screw likr parts of the shaft.

The shaft 5 may be a usual spiral drill, but for effecting a finishing work on the cylind rical faces of the bored hole it may be also provided with cutting layers 1 as shown in Fig. l2. These cutting layers may be formed by spiral ylinder parts bent to screw lines so as to cover the circumferential faces of the shaft, or it nay be produced by spirally working an annular cylinder. in this way it also possible to produce multiple toothed roaches or rrainers, hclicoidal milling cut-- circular lo: and the like. The shaft. provided with the necessary pro ections in the unner of tapping teeth or teeth.

of a file, and. at the outer circumference of these projections, the cutting layers 1 are piovided.

According to Figs. 13 and 1-1 a screw bolt cutter with square. screw threads has the main cutting faces of the latter covered by cutting layer or a pile. of cutting layers by being manufactured out of a raw piece as shown in Fig. 14:, consisting of an annular cylinder with the hardest layer inward. Screw nut cu: ing taps may inversely be manufactured out of a raw piece composed of a soft core and enveloping layers of gradually increasing hardness. It is also possible to produce screw thread cutting instruments with completely covered cutting faces by depositing the different layers electrically or by a metal spouting device.

With the knowledge of the described tools it is easy to manufacture still further kinds of tools in the new manner. For instance cir cular saws and grooved circular cutters are combinations of the devices shown in Figs. 4 and 8.

The cutting layers may consist of any useful materials, for the hardest layers. If materials are used which can not be welded or otherwise physically fastened, the cutting plates are fastened by aid of clamps, pressing plates and the like, especially in heavy tools.

I claim:

1. A tool comprising in combination a tool body, there being a front face and a rear face adjoining in a cutting edge on said body, and a. pile of layers of material of gradually increasing hardnesses, applied to the said rear face, the hardest layer being on the outer side and the tool body being of softer material, than the softest layer.

A tool with cylindrical shape and cut ting end face, comprising in combination, a shaft of the type of spiral drills and a drill head fastened to said shaft on one end and consisting of at least two screw thread like parts which join together by a common central part, each screw thread like part consisting of at least two layersof materials of gradually layer being outermost for engaging the work and the bodyof the drill proper being of a material softer than any portion of the layerformed cutting edge.

In witness whereof I affix my signature.

increasing hardnesses, the hardest 

